Real-time visualization of Karman vortex street in water flow field by using digital holography

The three-dimensional flow field generated by a feeding calanoid copepod measured using digital holography.

Digital in-line holography is used for measuring the three-dimensional (3-D) trajectory of a free-swimming freshwater copepod Diaptomus minutus, and simultaneously the instantaneous 3-D velocity field around this copepod. The optical setup consists of a collimated He-Ne laser illuminating a sample volume seeded with particles and containing several feeding copepods. A time series of holograms i...

Real Time Temperature Distribution Measurement of a Microheater by Using Off-Axis Digital Holography

Observation of Karman Vortex Street on Flowing Soap Film behind Cylinders at Low Reynolds Numbers

Introduction. The Karman-vortex street formed behind two-dimensional bluff bodies has attracted interest because of its beautiful flow pattern. It goes without saying that this beautifulness results from the alternative vortices regularly shed from the body. Vortex shedding induces aerodynamic force perpendicular to the mean flow. This force causing mechanical vibration of the model is accompan...

Control of Karman Vortex Street behind a Thin Airfoil at Low Reynolds Number

To control the Karman vortex street formed behind a thin airfoil at a certain incidence, a control cylinder was placed at the suction side apart from the airfoil in the downstream region. Both smoke visualization and hot-wire measurements confirmed that the Karman vortex street was completely suppressed. The mechanism for suppression of the vortex street was examined with a hot-wire survey.

Real-time blood flow visualization using the graphics processing unit.

Laser speckle imaging (LSI) is a technique in which coherent light incident on a surface produces a reflected speckle pattern that is related to the underlying movement of optical scatterers, such as red blood cells, indicating blood flow. Image-processing algorithms can be applied to produce speckle flow index (SFI) maps of relative blood flow. We present a novel algorithm that employs the NVI...